Results in 2001: Adenovirus vector containing hepatocyte growth factor cDNA (AdHGF) was propagated in 293 cells and concectrated with purification. Vascular endothelial cells (ECs) were isolated from canine jugular vein and cultured in M199+10%FCS. Cytotoxicity and HGF production were investigated to determine the most effective dose of AdHGF. As a result, it was concluded that 50 PFU of AdHGF per cell were the most effective dose.Results in 2003: Replacement of IVC with PTFE graft where AdHGF-transfected ECs were seeded was performed using 5 dogs after right hepatectomy. Two out of 5 dogs were survived, but three other dogs were dead within a week after the operation. Causes of death included untolerable damages and bleeding by the operation. Survived two dogs were sacrificed 4 weeks after the operation to investigate the liver regeneration and seeds grafts. There was no clot adherent to the graft where viable ECs were attached. Liver regeneration of hepatectomized dogs with seeded IVC graft was not different from hepatectomized dogs with unseeded graft. Serum concentrations of HGF were measured in the operation. However, levels of HGF in all serum samples were less than measurable ones. It is suggested that HGF expression levels from AdHGF-transfected ECs on the graft might not be enough to show biological activity.